After considering people's input on the team credit issue,
we've decided to use policy B.
In this policy, when a user belongs to a team and earns credit,
that credit is added to the team's total,
and the team keeps the credit even if the user leaves the team.
This provides a stronger and more meaningful form
of team identity and competition because "team-hopping" users
cannot cause team totals to suddenly decrease.
To implement this, we added a "team ID" field to the database result table;
it records the team ID of the user at the time the result is reported.
This field will enable us, if necessary, to reconstruct the
team totals in case they get out of synch.
Team recent average credit is computed the same way as for users and hosts;
if a team becomes inactive, its recent average credit
will eventually decay to near zero.
Team credit accounting (to reiterate) is independent of user accounting.
A user't credit total includes all granted credit,
regardless of team membership.